remove djcelery from tests

djcelery is only required for using the django result backend, or
admin, neither of which we are using during tests

celery_haystack/test_settings.py

@@ -12,7 +12,6 @@ TEST_ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), 'tests'))
 
 INSTALLED_APPS = [
     'haystack',
-    'djcelery',
     'celery_haystack',
     'celery_haystack.tests',
 ]

requirements/v2.txt

 django-discover-runner
 django-haystack
-django-celery
 celery
 Whoosh
 flake8